The animal Core Unit is serving as a resource to the following projects: Project 0044 "Growth Factor Signal Transduction Elements in Respiratory Tissues". Project 0046 "Mechanisms of Cytochrome P450 Gene Expression in the Hyperoxic Developing Lung". Project 0049 "Physiological Effects of Surfactant Treatment in Human Premature Infants". The CORE provides physical facilities designed for sterile surgical instrumentation of acute or chronic animal preparations and subsequent physiological studies in vivo and post-mortem. Experienced personnel is available to conduct these procedures. Sheep and rodents are the predominant species used in this facility.